The present invention relates to the new and distinct hardy, herbaceous, hibiscus plant, Hibiscus ‘Holy Grail’ hybridized under direction of the inventor Aug. 7, 2015 at a wholesale perennial nursery in Zeeland, Mich. The new plant is a hybrid of the complex, unreleased, proprietary hybrid known as 12-166-5 times ‘Perfect Storm’ U.S. Plant Pat. No. 27,880. Into the trial process the new plant was assigned the breeder code labeled 15-85-1. Both parents have a complex mixture of species in them, comprising the species: moscheutos and coccineus. 
Hibiscus ‘Holy Grail’ was first asexually propagated in late summer of 2016 by sterile shoot-tip tissue culture and later by shoot tip cuttings at the same nursery in Zeeland, Mich. The resultant asexually propagated plants have been found to be stable and true to type in successive generations of asexual reproduction.